**Al-Cr-Cu-N**

(Al53Cr47)N and (Al47Cr34Cu19)N were deposited by means of cathodic arc evaporation. It was shown that the Cu is present mainly in metallic form. The alloying with Cu was found to decrease the hardness from 30 to 25 GPa [106].

#### *4.2. Coatings with the Addition of Rare Earth Elements*

The effect of Y and La has been studied in AlCrN-based coatings.
